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C. Pucheu-Haston1
1Louisiana State University- School of Veterinary Medicine, Veterinary Clinical Sciences, Baton Rouge, USA
CM Pucheu-Haston, DVM, PhD, DACVD
Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
When the word “emergency” is spoken, dermatologic conditions are not the  rst ones that come to mind. Nonetheless, there are a number of rather serious and life-threatening conditions that can manifest entirely or partially on the skin. The purpose of this lecture is to discuss a few of these conditions.
Erythema multiforme / Stevens-Johnson syndrome / Toxic epidermal necrolysis:
These conditions are immune mediated disorders that may manifest in the skin, mucocutaneous junctions and mucous membranes. In humans, the clinical and etiologic differences between these syndromes are fairly well de ned. Characterization and differentiation of the syndromes is less well de ned and somewhat controversial in the dog, and considerable overlap between the three conditions may be seen.
Clinical appearance:
Erythema multiforme (EM) is typically characterized by the development of erythematous macules, papules or raised circular, serpiginous or arc-shaped plaques. Vesicles, bullae or ulcers may be seen but are typically not the predominant lesion. One or more mucosal surfaces may be affected.
Stevens Johnson syndrome (SJS) and Toxic epidermal necrolysis (TEN) typically appear as erythematous macules and patches, which subsequently develop areas of epidermal detachment. The two syndromes differ primarily with regards to the extent of the lesions, with SJS typically involving <10% of the body surface area, TEN involving >30% of the body surface area and an SJS/TEN overlap involving between 10-30% of the body surface. Mucous membranes and footpads are commonly involved. Patients are often systemically ill.
Because there is a lack of consensus with regards to
the exact de nition of these syndromes in veterinary medicine, the identity of potential triggering factors is poorly de ned. In many (and perhaps the majority) of cases, no clear trigger can be identi ed. Other putative triggers include drug administration, neoplasia, infections, vaccinations, and dietary items. Drug administration is more likely to represent a trigger for SJS/TEN than it is for EM.
Differential diagnoses would include exfoliative staphylococcal pyoderma, eosinophilic dermatitis /
Wells syndrome, sterile neutrophilc dermatitis (Sweet’s syndrome) and cutaneous lymphoma. A thorough
history must be obtained, focusing on the administration of recent medications (including vaccines, heartworm and  ea preventatives), exposure to other animals with infectious diseases and/or presence of signs consistent with infectious disease. Skin scrapings, bacterial and dermatophyte cultures may be appropriate to rule out other differentials. Bloodwork (complete blood count, chemistry pro le, urinalysis) is appropriate both to determine the extent of systemic involvement and to provide a reference for therapeutic monitoring. Thoracic and abdominal imaging may be appropriate to investigate the potential for neoplasia. Skin biopsy will be important to support the clinical diagnosis, although the practitioner must be aware that there may be considerable histologic overlap between the two conditions.
Clinical management:
Therapy for these conditions is mostly supportive, including analgesic therapy,  uids and nutritional support. The prophylactic use of systemic antibiotics is somewhat controversial and likely should be avoided except in cases of severe epidermal loss. If a drug reaction is suspected, all drugs not essential for life should be promptly discontinued.
Topical therapy plays an important role in management. Frequent cleansing with gentle antiseptic products is
an appropriate approach to the prevention of infection. Patients with extensive erosion or serum oozing may bene t from gentle hydrotherapy or whirlpool treatment to help remove surface debris and bacteria. A light application of topical antimicrobial agents (such as silver sulfadiazine) may be helpful, but care must be taken to avoid overapplication, which will result in maceration of the skin.
An Urban Experience

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